DESMOPLASTIC AND DESMOPLASTIC NEUROTROPIC MELANOMA - EXPERIENCE WITH 280 PATIENTS

BACKGROUND. It has been suggested that desmoplastic melanoma (DM) and desmoplastic neurotropic melanoma (DNM) are associated with worse prog noses and higher local recurrence rates than other forms of melanoma. In the current study, a large series of patients with DM and DNM treat ed at a tertiary referral center was reviewed. METHODS. For 190 patien ts with DM and 90 patients with DNM accrued over a 10-year period, cli nical features were recorded and all available histopathology was revi ewed. The associations between clinical and pathologic variables, biol ogic behavior, and eventual outcome were analyzed. RESULTS. The male-t o-female ratio was 1.75:1 and the median patient age 61 years. The med ian tumor thickness was 2.5 mm, and 44% of cases were amelanotic. Five -year survival was 75%. Significant predictors of overall survival wer e a high mitotic rate (P = 0.003) and tumor thickness (P = 0.011). All the DNMs exceeded 1.5 mm in thickness and were graded as Clark's leve l IV or V. There was a significant increase in local recurrence when n eurotropism was present (P < 0.001). The rate of local recurrence was not higher for Dh? than for other cutaneous melanomas. CONCLUSIONS, Th ere was no statistically significant difference in survival for patien ts with DM and those with DNM, and overall survival for both was simil ar to that for patients with other cutaneous melanomas. However, there was a lower rate of regional lymph node metastasis at initial present ation and as the first recurrence for both DM and DNM. The local recur rence rate was higher when the surgical clearance margin was <1 cm and when neurotropism was present. (C) 1998 American Cancer Society.